Melting, Boiling, and the Heat Needed to Change State

The amount of heat required to change 1 gram of ice at 0°C to 1 gram of water at 0°C is 80 calories. Is this statement true?

The heat of fusion of water is 80 calories per gram. How many calories are needed to change 10 grams of ice at 0°C to 10 grams of water at 0°C?

Answer = 1($)

Lead's heat of fusion is 5.9 calories per gram — much lower than water's. How many calories are needed to change 10 grams of solid lead at its melting point to liquid lead at that same temperature?

Answer = 1($)

Margarine softens gradually as it warms rather than melting suddenly at one fixed temperature. Based on this behavior, is margarine best classified as a crystalline or an amorphous solid?

Sort each property by the type of solid it describes

Sort each property by the type of solid it describes

The heat of vaporization of water is 540 calories per gram. How much heat is needed to change 10 grams of water at 100°C entirely to water vapor at 100°C?

Answer = 1($)

Which requires more calories per gram: melting ice, or vaporizing water?

Arrange these steps in the order you would carry them out to change 1 gram of ice at -20°C into water vapor at 130°C.

Given the specific heat of ice and of steam are both 0.5, find the total heat needed to change 1 gram of ice at -20°C to water vapor at 130°C, filling in each step:

• Heat the ice from -20°C to 0°C (\(H = m \cdot c \cdot \Delta T\)): 1($) cal
• Melt the ice to water at 0°C (heat of fusion = 80 cal/g): 2($) cal
• Heat the water from 0°C to 100°C: 3($) cal
• Vaporize the water at 100°C (heat of vaporization = 540 cal/g): 4($) cal
• Heat the steam from 100°C to 130°C: 5($) cal
• Total heat needed: 6($) cal

A warm liquid evaporates more quickly than a cool one because it has more ______ molecules capable of breaking free from the surface.

A warm liquid evaporates more quickly than a cool one because it has more ______ molecules capable of breaking free from the surface.

Match each term on the left with what happens at the molecular level on the right.

Match each term on the left with what happens at the molecular level on the right.